Should I terminate the trigger output of a spectrum analyzer when not used ?

[electronic_guy]

Hi,

I have an Agilent CSA N1996A spectrum analyzer. It comes with the trigger generator. I understand that open circuit in RF means reflection. In fact total reflection.

When I work with the the stimulus response mode I do not see a way to turn OFF the trigger source. As soon as I connect the cable from RF_out to RF_in it works, so I can see that the source stays active when I haven't connected anything.

I'm just wondering if this can damage my SA trigger source. I know modern SAs have some protection for reflection, but prolonged reflection can degrade the SA source. I think if this is the case then it's completely unnecessary damage.

So can you explain if this is an real concern for me to worry about in using a SA with trigger source, or for any RF signal generator for that matter ?

[electronic_guy]

Anybody wants to give this question a go.

[Bud]

Read the device User Manual. If there is nothing in it about terminating the unused ports, live them alone.

[DaJMasta]

Generally not important.  If your external trigger is running hundreds of MHz to GHz speed (repetitive or just edge speed), then maybe you have a reason to terminate, but generally these ports are marked that they need to be terminated when not in use and come with one attached (often physically, to the instrument).

If you actually mean tracking generator, the output frequency could certainly justify it, but these are generally designed to have sufficient protection from running as an open - it is test equipment, after all.  They're also usually not all that powerful in terms of maximum output level, so it doesn't take elaborate design or expensive parts for them to be protected from their own output power reflected back.